The present invention relates to servomotors in general, and more particularly to improvements in fluid-operated servomotors which can be utilized to actuate various types of aggregates, such as clutches in automotive vehicles. Still more particularly, the invention relates to improvements in servomotors of the type wherein a mobile component can perform a working stroke in response to the application of positive or negative pressure and performs a return stroke when the positive or negative pressure is reduced sufficiently to enable a restoring force to effect a movement of the mobile component back to its starting position. As a rule, the mobile component constitutes or resembles a piston.
More specifically, the invention relates to a servomotor which is provided with a device capable of compensating for wear, swelling and/or other unpredictable phenomena of various parts and is installed between the aforementioned mobile component and an output element, for example, an element which can transmit translatory and/or another form of motion to the disengaging mechanism of a clutch in an automotive vehicle.
It is already known to provide or combine a servomotor with a compensating device of the above outlined character. Reference may be had to German Pat. No. 2,428,645 which discloses a compensating device serving to eliminate play between motion transmitting and motion receiving parts. Such parts may include or constitute the linkage in a brake or clutch. The patented compensating device comprises a feed screw which is rotatable relative to a nut or vice versa to thereby compensate for play between motion transmitting and motion receiving parts. As a rule, the nut is rotated relative to the feed screw. The means for rotating the nut is a mechanical device of substantial complexity so that not only the initial but also the maintenance cost of such compensating devices is quite high. Furthermore, the patented compensating device exhibits the drawback that it is adjustable in a single direction only, namely, in a direction to compensate for play between motion transmitting and motion receiving parts.